Plate clamping mechanism for electrolytic treating apparatus



' Sept. 16, 1958 E. R. GUTZMER 2,352,463

PLATE CLAMPING MECHANISM FOR ELECTROLYTIC TREATING APPARATUS Filed Nov.14. 195s s sheets-sheet 1 f/llll. r/ lll/ll /ffy v 35 .ZzUe/zar 51702655Gazme Sept 15, 1958 E. R; GUTZMER 2,852,463

PLATE CLAMPING MECHANISMPOR ELEoTRoLYTIc TREATING APPARATUS Filed Nov.14, 195e :s sheets-sheet 2 afi/f2s'.

.IX/ F TATP T?zvcjrzzlvr EPH/655 R Gui'zmer' Sept. 16, 1958 E. R.GUTZMER PLATE CLAMPING MECHANISM FOR 'ELECTROLYTIC TREATING APPARATUSFiled NOV. 14, 1956 3 Sheets-Sheet 3 VII/Mill] PLATE CLAMPING MECHANISMFOR ELECTRO- LYTIC TREATING APPARATUS Ernest R. Gutzmer, Hinsdale, lll.,assignor to Intercompany Corporation, Chicago, Ill., a corporation ofIlhnols Application November 14, 1956, Serial No. 622,118 7 Claims. (Cl.204-242) This invention relates to a clamping mechanism that findsparticular use in combination with a plating rack for submerging andsupporting a sheet or plate within an electrolyte bath.

In the prior art, it has been customary to use racks for holding largesteel sheets during an electrotreating operation and the sheets orplates have been clamped onto the racks by means of lever clamps orclamping bolts. Such arrangements require considerable time to operateand unduly increase the cost of the treating operation. In addition,they require frequent replacement since, n the case of electroplating,the surfaces of the clamps become plated while, in the case ofelectropolishing, the surfaces of the clamps tend to disintegrate.

It is the principal object of the present invention to provide aclamping 'mechanism that overcomes the above disposed in the notches forgripping the plate against a contact surface that denes one side of thenotch. Preferably the tubing, the rack and the clamping mechanisms, withthe exception of the contact surface, are coated with an insulatingmaterial that resists the corrosive action of the electrolyte.

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modified rack construction that is useful with the present invention.

Referring now to the drawings and particularly to Fig. 1, a typicalelectrotreating arrangement is shown as comprising a tank for anelectrolyte bath, an anode 11, a cathode 12, and a source of D. C.current 13 conlnected across the electrodes 11 and 12 to send an ioncurrent, as indicated by the arrows 14, through the electrolyte from theanode to the cathode.

For purposes of illustration it will be assumed that the arrangement ofFig. 1 is used for electroplating steel sheets in which case the anode11 may be of lead or any other suitable material and the cathode 12, inthe form of a supporting rack (Fig. 2), carries a steel sheet having oneof its major surfaces 16, facing the anode 11 to receive the platingcurrent.

Other objects and advantages of the invention will become apparent asthe description proceeds.

In the accompanying drawings forming a part of this application and inwhich like numerals are employed to designate like parts throughout thesame;

Fig. l is a diagrammatic plan view of an electrotreating apparatus;

Fig. 2 is a front elevational View of a rack, according to theinvention, supporting a plate that is to serve as one of the electrodesof the apparatus of Fig. l, with parts of the rack `being broken awayfor purposes of illustration; i

Fig. 3 is a sectional view through a portion of the rack that is adaptedto be submerged in the electrolyte bath, and is taken along the line 3-3of Fig. 2;

Fig. 4 is a vertical sectional view taken along the line 4 4 of Fig. 2to illustrate the construction of one of the vertical legs of the rack;

Fig. 5 is a sectional view taken along the line 5-5 of Fig. 2;

Fig. 6 is a fragmentary vertical sectional view take along the line 6 6of Fig. 2; and

Fig.. 7 is a diagrammatic plan View of an alternative V arrangement ofelectrotreating apparatus illustrating a Preferably the rack comprises amain frame of aluminum welded construction that consists of a forwardlyfacing, channel-shaped, horizontal member 18, a pair of rearwardlyfacing, channel-shaped vertical legs 19 (see Fig. 4) carried by themember 18, and a pair of upper and lower, horizontally extending,aluminum cross bars designated 20 and 21 respectively (Fig. 3) that areconnected between the legs 19; and a 1r shaped subframe of copper weldedconstruction and comprising a horizontal member 22 that nests within theforwardly facing aluminum channel 1S, and a pair of depending verticallegs 23 that overlie the rearwardly facing aluminum channels 19. Thecopper subframe is lixedly mounted on the aluminum main frame and.rivets, such as shown at 24 in Fig. 4, are preferred for this purpose.

Finally the rack includes upper and lower aluminum contact bars (Fig.3), designated 25 and 26 respectively, that are attached to the upperand lower cross bars 20 and 21, by suitable screws 27, to cooperatetherewith in providing a pair of clamping mechanisms for grippingopposite edges of the sheet 15. The upper contact bar is provided with acontact surface 28 and the lower contact bar is provided with a contactsurface 29 for estab lishing the necessary electrical contact with thesheet 15. With the exception of the contact surfaces 28 and r29 all ofthe exposed porti-ons of the rack that are intended for submergence inthe electrolyte are provided with a coating 30 of insulating materialthat is capable of resisting the corrosive action `of the electrolyte.For this purpose a vinyl plastic is preferred, though any other suitablematerial may also be employed.

One of the principal advantages of the invention resides in the factthat there are no exposed surfaces `which will become plated by theelectrolyte and hence the rack is not subject to becoming coated withthe plating material. To accomplish this goal a system of inatablepneumatic tubing of a material that is substantially unaffected by theelectrolyte, is mounted on the rack in association with the contactsurfaces 28 and 29 to grip the sheet against these surfaces. The tubingis preferably made of a gum rubber or other suitable inatable materialthat is capable of returning to its original size and shape afterv'being subjected to internal pressure. The gum rubber is resistant tothe action of most plating solutions but even when it is adverselyaffected it will stand up for a number of weeks.- Of course, 4anymaterial that better achieves the general purpose outlined above wouldbe preferred.

As is best seen in Fig. 3, in the preferred arrangement of the clampingmechanisms, the upper aluminum cross bar 20 includes a laterally orrearwardly offset recess at its lower end and a forwardly projectingledge 32 at its upper end, with the ledge having a series of tappedbores 33 cooperating with the screws 27 to secure the upper contact bar25 in spaced relation to the remainder of -cross b'ar .20 .to define.therewith a horizontally elongated, .downwardly facing plate receivingnotch that extends substantially the entire length of the cross bar andthat includes a generally semi-circular pocket which connesa length ofpressurized-pneumatic tubing 36. In a p-deiine, therewith, ahorizontally elongated upwardly facing plate receiving notch thatextends substantially the "entire length of cross bar 21 and includes agenerally Asemi-circular pocket .in which is confined another length ofpressurized tubing 36.

.Preferably the upper cross member 20 and the upper :contact bar 25 aresomewhat wider than the lower cross .member 21 and the lower contactbar.26 and the arrangement is such that the upper notch is considerablydeeper than the lower notch. The depth of the notches is correlated sothat in locating the sheet it is lirst inserted into the upper notch asuicientfdistance to permit the bottom end of the sheet to clear thelower contact bar 25. The sheet Vis then swung inwardly and lowered intothe bottom notch until it assumes the position shown in Fig. 3. Duringthe insertion or removal of the sheet 15 thepneumatic tubing 36 is inits deflated condition to provide the necessary clearance.

Referring again to Fig. 3, it will be seen that the upper portion ofcontact surface 28 is exposed to the electrolyte but due to thearrangement of the clamping mechanisms, substantially no plating will bedeposited on this exposed surface. It will be seen that as viewed inFig. 3 the ion path 14 approaches from the left and would have to followa tortuous path in order to actually contact surface '2S and in practicethis simply does not occur. This fact would also indicate that theclamping tubings location is effectively shielded from the platingdeposits and hence, even if there were exposed surfaces in thislocation, there is little likelihood that they would become coated.

Obviously the mounting of the sheet 1S may be handled in other ways. Forexample, the sheets are usually suflciently thin that they may be bowedto foreshorten them sutliciently to permit their direct insertion intothe notches. Alternatively, the notches may be opened at their endstojpermit the sheets to be moved into place from the side.

In Fig. 2 the lengths of pneumatic tubing 36 are shown connected to asystem of tubing 40 which in turn is connected to a source of airpressure (not shown) for inating the pneumatic tubing. The connectionbetween the copper tubing and the pneumatic tubing is accomplished 'byproviding a stepped plug 41 which may also be of gum rubber which isinserted through the open end of `the pneumatic tubing and whichincludes a pair of intersecting axial and transverse bores, designated42 and 43 respectively. The axial bore 42 opens into the pneumatictubing 36 and the transverse bore 43 receives a nipple 44 adapted forconnection to the copper tubing 40. The nipples pass through appropriateaccess notches 45 provided in the contact bars.

It is 'a matter of choice whether the copper tubing is permanentlyconnected to the pneumatic tubing, in which case the copper tubingconstantly is submerged in the electrolyte and hence must be coated withvinyl plastic. Alternatively the copper tubing can be temporarilyconnected to the nipples 44 for inilating the pneumatic tubing. In thislatter instance, the nipples would include an air valve of the typecommonly used in automobile tires and the nipple and valve would besuitably masked to prevent exposure to the electrolyte.

The assembly and operation of the device is exceedingly simple. Prior tothe mounting of the contact bars the lengths of pneumatic tubing areinserted in the pockets formed in the aluminum cross bars. Finally thecontact .bars .are screwed in place and thescrews 27 are .masked off.The sheet 15 to be plated is then inserted and the pneumatic tubing isinflated to grip the sheet against the contact surfaces 28 and 29. Afterthe plating operation is completed the tubing is deated to permit theremoval of the sheet. It will be apparent that a single simplifiedcontrol can be employed for applying and releasing the clampingpressuresand furthermore the parts of the rack and clamping mechanismare entirely free from the action of the electrolyte and are not subjectto becoming plated.

The use of inflatable tubing for applying the clamping pressures has theadditional advantage that sheets o'r vother articlesof irregular contourcan readily be gripped by the tubing. In such instances the tubingmerely distorts to assume the contour of the 'surface against which itis engaged and this insures a more uniform gripping action irrespectiveof the surface contour of lthe article being held.

The concepts 'of the Vinvention find application in a variety ofsupporting arrangements, one such additional arrangement being shown inFig. 7. In this instance the tank for the electrolyte bath, as shown at5l), is of circular configuration and Vmay itself be provided with alead coating in 'order that it will serve as the anode. The rack is-designated generally at 51 and it includes a pair of complementaryclamping mechanisms 52 and 53, each of which is formed with elongatedopen faced notches 54 for gripping the opposite ends of a steel sheet 15which again .serves as the cathode. The exterior D. C. source .is againshown at 13.

The arrangement of Fig. 7 is frequently useful for the .plating ofrelatively thin sheets and the sheet is shown bent around a number ofsupport posts 56 with one of .its major surfaces facing the circularanode 50. Each of the clamping mechanisms again includes alength ofinflatable tubing 36 carried in a laterally offset pocket and grippingthe edges of the sheet against contact surfaces "57. Finally the nipples44 are shown for connection to a source of air pressure. In thisinstance also, the supporting rack 51, with Ithe exception of thecontact surfaces 57, is coated with a vinyl plastic to protect it fromthe Velectrolyte and to prevent coating of the rack. This arrangementoiers the same advantages as does Ithe clamping arrangement shown inFigs. 1 to 6.

It should be understood that the description ofthe preferred form of theinvention is for the purpose of complying with section 112, Title 35 ofthe United States Code, and that the appended claims should be construedYas broadly as the prior art will permit.

I claim:

l. In apparatus for the electrolytc treating of a plate, said apparatusincluding a reservoir for an electrolyte bath; an electrode submerged insaid bath', a rack for supporting 'said plate in said bath with a majorsurface of said plate facing said electrode, said rack including a pairof cooperating clamping mechanisms gripping opposite edges -of theplate, and intermediate structure connected between said clampingmechanisms and holding them in predetermined spaced relationship; and acurrent source connected to said electrode and to said clampingmechanisms: the improvement wherein each of said clamping mechanisms hasan elongated openfaced plate receiving notch defined in part Ibylaterally spaced elongated interior wall surfaces with one of saidsurfaces being formed of current conducting material and 'establishingelectrical contact between the majorsurface of said plate and saidclamping mechanism, hollow pressurized members of inatable materialdisposed lin s'ai'dnotch'es in facing relation to "said-surfaces ofcurrentconducting material to grip said plate against said lastmentionedsurfaces, and means for varying the pressure in said hollow members.

I2. .In apparatus for the electrolytic treating of` a plate, saidapparatus including a reservoir for an electrolyte bath; an electrodesubmerged in said bath; a rack for supporting said plate in said bathwith a major surface of said plate facing said electrode, said rackincluding a pair of cooperating clamping mechanisms gripping oppositeedges of the plate, and intermediate structure connected between saidclamping mechanisms and holding them in predetermined spacedrelationship; and a current source connected to said electrode and tosaid clamping mechanisms: the improvement wherein each of said clampingmechanisms has an elongated open-faced plate receiving notch defined inpart by laterally spaced elongated interior wall surfaces with one ofsaid surfaces being formed of current conducting material andestablishing electrical contact between the major surface of said plateand said clamping mechanism, elongated pressurized pneumatic tubingconfined in each notch to hold said plate against said one surface, andmeans for varying the pressure in said tubing.

3. ln apparatus for the electrolytic treating of a plate, said apparatusincluding a reservoir for an electrolyte bath; an electrode submerged insaid bath; a rack for supporting said plate in said bath with a majorsurface of said plate facing said electrode, said rack including a pairof cooperating clamping mechanisms gripping opposite edges of the plate,and intermediate structure connected between said clamping mechanismsand holding them in predetermined spaced relationship; and a currentsource connected to said electrode and to said clamping mechanisms: theimprovement wherein each of said clamping mechanisms has an elongatedopenfaced plate receiving notch defined in part by laterally spacedelongated interior Wall surfaces, pressurized pneumatic tubing disposedin each of said notches laterally of the open faces therein to reactagainst one of said surfaces and grip said plate Iagainst the other ofsaid surfaces and establish electrical contact between said plate andsaid clamping mechanisms, and means for varying the pressure in saidtubing.

4. In apparatus for the electrolytic treating of a plate; said apparatusincluding a reservoir for an electrolyte bath; an electrode submerged insaid bath; a rack for supporting said plate in said bath with a majorsurface of said plate facing said electrode, said rack including a pairof cooperating clamping mechanisms gripping opposite edges of the plateand intermediate structure connected between said clamping mechanismsand holding them in predetermined spaced relationship, and a currentsource connected to said electrode and to said clamping mechanisms: theimprovement wherein each of said clamping mechanisms has an elongatedopenfaced plate receiving notch defined, in part, by laterally spacedelongated interior wall surfaces, one of said notches being deeper thanthe other to facilitate the mounting of a plate therein, pressurizedpneumatic tubing disposed in each of said notches laterally of the openfaces therein to react against one of said surfaces and grip said plateagainst the other of said surfaces and establish electrical contactbetween said plate and said clamping mechanisms, and means for varyingthe pressure in said tubing.

5. A plate supporting rack for use in the electrolytic treating of aplate and comprising a pair of cooperating clamping mechanisms forgripping opposite edges of the plate, and intermediate structureconnected between said clamping mechanisms and holding them inpredetermined spaced relationship, each of said clamping mechanismsincluding an elongated--openfaced notch defined in part by laterallyspaced elongated interior wall surfaces, elongated pressurized pneumatic`tubing disposed in each of said notches laterally of the open facestherein to control said plate and react against one of said surfaces andgrip said plate against the other of said surfaces to establish anelectrical connection between said plate and said clamping mechanism,and means for varying the pressure in said tubing, said rack, with theexception of said other surfaces, being coated with an acid resisting,insulating material.

6. In apparatus for the electrolytic treating of an article;saidapparatus including a reservoir for an electrolyte bath; anelectrode submerged in said bath; a rack for supporting said article insaid bath in operative relationship to said electrode, and a currentsource connected to said rack and said electrode: the improvementwherein said rack includes means providing an elongated openfacedarticle receiving notch defined in part by laterally spaced elongatedinterior wall surfaces, pressurized pneumatic tubing disposed in saidnotch laterally of the open face thereof to react against one of saidsurfaces and grip said article against the other of said surfaces toestablish electrical contact between said article and said rack, andmeans for varying the pressure in said tubing.

7. In apparatus for the electrolytic treating of a plate, said apparatusincluding a reservoir for an electrolyte bath; an electrode submerged insaid bath; a rack for supporting said plate in said bath with a majorsurface of said plate facing said electrode, said rack including a pairof cooperating clamping mechanisms gripping opposite edges of the plate,and intermediate structure connected between said clamping mechanismsand holding them in predetermined spaced relationship; and a currentsource connected to said electrode and to said clamping mechanisms: theimprovement wherein said clamping mechanisms have exposed surfaces ofcurrentconducting material disposed along opposite edges of one of themajor surfaces of said plate for current-conducting contact therewithand said clamping mechanisms include hollow pressurized members ofinflatable material disposed along and in facing relation with saidexposed surfaces to engage the other major surface of said plate andgrip said plate against said exposed surfaces, and means for varying thepressure in said hollow members.

References Cited in thefile of this patent UNITED STATES PATENTS 804,429Petz Nov. 14, 1905 1,872,221 Bart Aug. 16, 1932 2,190,440 Beebe Feb. 13,1940 2,248,718 Owen July 8, 1941 2,382,958 Burgoine et al. Aug. 21, 19452,713,555 Neely July 19, 1955

1. IN APPARATUS FOR THE ELECTROLYTIC TREATING OF A PLATE, SAID APPARATUSINCLUDING A RESERVOIR FOR AN ELECTROLYTE BATH; AN ELECTRODE SUBMERGED INSAID BATH; A RACK FOR SUPPORTING SAID PLATE IN SAID BATH WITH A MAJORSURFACE OF SAID PLATE FACING SAID ELECTRODE, SAID RACK INCLUDING A PAIROF COOPERATING CLAMPING MECHANISMS GRIPPING OPPOSITE EDGES OF THE PLATE,AND INTERMEDIATE STRUCTURE CONNECTED BETWEEN SAID CLAMPING MECHANISMSAND HOLDING THEM IN PREDETERMINED SPACED RELATIONSHIP; AND A CURRENTSOURCE CONNECTED TO SAID ELECTRODE AND TO SAID CLAMPING MECHANISMS: THEIMPROVEMENT WHEREIN EACH OF SAID CLAMPING MECHANISMS HAS AN ELONGATEDOPENFACED PLATE RECEIVING NOTCH DEFINED IN PART BY LATERALLY SPACEDELONGATED INTERIOR WALL SURFACES WITH ONE OF SAID SURFACES BEING FORMEDOF CURRENT CONDUCTING MATERIAL